Coal India Limited's 'Betty' The 2'0" gauge Coal India network in the North East corner of Assam used a number of small 0-4-0 saddle tank locomotives built by W G Bagnall of Stafford. 'Betty' dating from 1931 was at work at Tirap mine on 1979.01.24 The wagons in the background are on the NEFR metre gauge system.